The present invention relates to a device for detecting an electric discharge position between a workpiece and a wire electrode in a wire electric discharge machine.
Generally known are various methods for detecting an electric discharge position in an electric discharge machining apparatus. These methods include a method (see Japanese Patent Disclosure No. 59-47124) in which the electric discharge machining position is detected by measuring the propagation time of pressure waves produced when electric discharge is caused, a concentrated electric discharge detecting method (see Japanese Patent Disclosure No. 59-30620) in which whether the electric discharge position is concentrated on one point is determined in accordance with discharge current waveforms, and a method (see Japanese Patent Disclosure No. 53-64899) in which the electric discharge position is detected by detecting the variation of an electric resistance between a point of electric power supply to a wire electrode and an electric discharge point.